With the rapid downsizing of information processors, the environment thereof has become one in which a network can be easily built even in a small-scale office.
In such an environment, users require printers to be small-size, high-speed color ones as output apparatuses.
Also in the field of network printers, therefore, the mainstream is small-sized network printers which are adapted to A4-size and can be installed on a desk in an office.
The size of a laser beam printer used as a prior-art network printer is determined by the size of the paper cassette, the photosensitive belt and the transfer drum because in the printing process of the printer paper sheets are printed one by one. The size of the fixation unit is determined by the cooling efficiency relative to the printing speed since the toner is thermally fixed.
Accordingly, the external dimensions of the printer are determined by the printing sheet size and the printing speed, and so designed as to be minimums.
With the prior art, the volume of the apparatus is substantially determined by the sheet size and the printing speed. In view of the reduction of the size of the apparatus, therefore, it is effective to minimize the installation area.
Since, however, the paper cassette is usually provided at the bottom part of the apparatus, the prior art has the problem that the installation area also cannot be further decreased.